Self-discharging finishing mill



` Jan. 2.1, 1969 R. K. MCKIBBEN SELF-DISCHARGING FINISHING MILL FiledFeb. 7, 1966 Flai-l l lllsl RICHARD K. Mc KIBBEN I NVENTOR.

ATTORNVEYS .a of 5 INVENTOR.

ATTORNEYS Jan- 21, 1969 R. K. McKlBBEN SELF-DISCHARGING FINISHING MILLSheet Filed Feb. 7, 1966 Sooo I-l-I- I-l' RICHARD K. MC KIBBEN Sheet -3of 3 R. K. MCKIBBEN SELF-DISCHARGING FINISHING MILL ATTORNEYS Jan. 21,1969 United States Patent O 8 Claims ABSTRACT OF THE DISCLOSURE Avibratory mill having an annular container and means for vibrating thecontainer. The bottom of the container includes a ledge, and a ramp isextensible from the ledge to convey media and work pieces beyond theledge for enabling discharge of at least the work pieces.

This invention relates to self-discharging finishing mills, moreparticularly, to the type of mill utilizing a vibrating unit such as themill disclosed in U.S. Patent No. 3,100,- 088, issued Oct. 20, 1961, toHenry L. Podmore. Included in the objects of this invention are:

First, to provide -a vibratory finishing mill which includes a toroidalcontainer having a helical bottom terminating in a ledge over which thefinishing media and work pieces cascade during the finishing operationand which incorporates a novel travelling ramp capable of helic-almovement in a path continuing from the ledge and adapted to bridgebetween the ledge and a separator grid for condu-cting the media andwork pieces to the grid to discharge the work pieces and return themedia to the container.

Second, to provide a vibratory finishing mill and method of finishingwherein the mill is initially filled to a level above the ledgeseparating the upper and lower ends of the helical bottom. The mill isthen vibrated in such a manner that the media and work pieces movetoroidally, and advance circumferentially up the helical bottom andcascade over the ledge; the vertical depth of the mass decreasing towardthe upper end of the helical bottom and the rate of progressionincreasing so as to minimize the difference in level of the mass abovethe upper and lower levels of the helical bottom `and protect the workpieces as they move over the ledge.

Third, to provide a vibratory finishing mill and method of finishingwherein vibration of the mill is utilized to facilitate extension of thetraveling ramp through the cascading mass of media and work pieces,thereby permitting automatic discharge of the work pieces after apredetermined interval.

With the above and other objects in view as may appear hereinafter,reference is directed to the accompanying drawings, in which:

FIGURE l is a side view of the finishing mill with portions broken awayand in section.

FIGURE 2 is a plan View thereof with portions broken away and insection.

FIGURE 3 is a diagrammatcal developed view corresponding to the mid-lineof the annular chamber and indicating the surface of the contents priorto and during operation of the mill.

FIGURE 4 is a fragmentary sectional view taken through 4--4 of FIGURE 2showing the travelling plate or ramp in its retracted position.

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FIGURE 5 is a fragmentary sectional view similar to FIGURE 4 showing theramp in its extended position.

The finishing mill includes a base 1 on which is mounted a ring ofsprings 2 joined at their upper ends to a mounting ring 3.

Secured to the mounting ring 3 is an annular bottom plate 4 throughwhich extends a central tube 5. The tube 5 extends below the bottomplate 4 and is rigidly supported relative thereto by gussets 6. Mountedin the lower extended portion of the tube 5 is a motor 7 havingeccentric weights 8 at opposite ends thereof.

The central tube 5 also extends above the bottom plate 4 and theperiphery of the bottom plate supports an outer shell 9 which forms withthe central tube 5 an annular space. Fitted within the annular space islan Aannular container 10 having a radially inner wall 11 and a radiallyouter wall 12 and a helical bottom 13.

The helical bottom is provided with an upper end 14 I and a lower end 15joined by a ledge 16. The lower part of the ledge forms a curvedtransition portion 17.

The major portion of the space between the annular container 10 and thew-alls formed bythe central tube 5, bottom plate 4 and outer shell 9 isfilled with a vibration transmitting packing 18 which may be a rigidfoamed plastic material. The space under the upper portion of thehelical bottom 13 extending backward from the ledge 16 is free ofpacking and forms a compartment 19.

The inner surface of the annular container 10 is covered with awear-resistant liner 20. Cast polyurethane has been found satisfactory,but other materials, preferably having elastomeric qualities, may beused.

Above the ledge 16, there is provided a wear-resistant lip 21 which ispreferably arranged so that it may be removed. The lip overhangs theupper portion of the ledge and terminates in lateral margins 22 fittedonto the inner Aand outer walls of the wear resistant liner 20.

Underneath the lip 21, the ledge 16 'is provided with a guide slot 23extending the width ofthe container and communicating with thecompartment 19. Mounted within the compartment adjacent the ledge 16 isa guide frame 24 which is arcuate in plan conforming to the curvature ofthe container 10. The guide frame is :supported on suitable posts 25which-are adjustable. The guide frame 24 supports an arcuate travellingplate or ramp 26 which is adapted to project circumferentially from theledge 16.

Formed in the linercovering the radially inner and outer walls 11 'and12 of the container is a pair of arcuate guide ledges 27 which form acontinuation of the guides formed by the guide frame 24 so that when thetravelling plate or ramp 26 is extended, its lateral sides aresupported. It has been found desirable to provide clearance slots 28 inthe guide ledges 27 immediately beyond the lip 21 and immediately beforegrid 34.

Mounted in the compartment 19 is a drive unit 29 for advancing andretracting the travelling blade 26. The drive unit comprises a cylinder30 supported within the compartment by a universal bracket 31. A thrustshaft 32 extends from the cylinder and is joined by a universalconnection 33 to an inner end of the traveling blade 26.

The travelling blade is prefer-ably formed off the ysame wear-resistantmaterial from which the liner 20 is formed and may be a solid piece ofsuch material or may contain suitable reinforcing.

Beginning at a point circumferentially displaced from the ledge 16 landjoined to the terminal ends of the arcuate ledges 27 is a grid orseparator 34 which extends essentially horizontally andcircumferentia-lly to a workpiece discharge chute 35. The grid 34 isprovided with a wall 36 so that workpieces on the grid are deflectedtoward the chute 35.

The lower end of the helical bottom 13 beyond the ledge 16 is providedwith a drain 37 which may be equipped with -a shut-oil valve, not shown.A fluid supply pipe 38 overhangs the container 10 and is provided with adischarge nozzle 39. Other spray means, not shown, may be located overthe grid 34.

The method of finishing material utilizing the finishing mill is asfollows:

Suitable finishing `media is placed in the container until the containeris filled to a level 40 substantially above the upper end 14 of thehelical bottom, as indicated by broken lines in FIGURE 3. The parts orworkpieces to be finished are added to the media. The container is thenvibrated by means of the motor 7 and weights 8.

The motor and its weights may be adjustable vertically as a unit so asto be located at the best level with respect to the center of gravity ofthe container and its contents and the circumferential relationship ofthe two weights are so adjusted that the contents comprising media andworkpieces tend to advance or progress clockwise as viewed in FIGURE 2;that is, lfrom the lower end to the upper end of the helical bottom 13.

In addition, the media and parts churn in a toroidal pattern; that is,they move upwardly at the radially outer side of the container, thenradially inward across the top, then downward along the radially innerside of the container and finally, radially inward as indicated by thearrows in FIGURE 4.

Due to the helical shape of the bottom 13, the center of mass of`material comprising the media and parts, is located eccentrically withrespect to the center of the container; that is, the center of m'ass isdisplaced toward the lower end of the helical bottom 13. As a result,the amplitude of the vertic-al component of vibration tends to increasein a direction toward the upper end 14 of the helical .bottom 13. Itseems from observation of the machine in operation, that this increasein amplitude of the vertical component tends to accelerate the material.In any case, the vertical depth of the material decreases toward theupper end 14 of the helical bottom 13. Consequently, the difference inlevel of the material overlying the upper end 14 and the materialoverlying the lower end 15 is substantially less than the verticalheight of the ledge 16 so that the media and workpieces cascade over theledges in such -a manner that the workpieces are fully supported and arenot subject to damage which might be the case if the workpieces were tofall freely. The characteristic outline of the upper surface of the-material during operation of the finishing mill is illustrated bydashlines 41.

The material is vibrated and circulated around the cont-ainer until theworkpieces are properly finished, whereupon, the drive unit 29 isactivated to thrust the travelling blade 26 circumferentially until itsextended end engages or overlies the grid 34. This movement isaccomplished while the finishing mill remains in operation.

Vibration of the finishing mill is continued, causing the workpieces andmedia to pass onto the grid. The workpieces are delivered to thedischarge chute 35, while the media is returned to the lower end forrecirculation. After the workpieces have been discharged, the travellingblade 26 is retracted and additional workpieces are added to the media.This may be accomplished without stopping operation of the finishingmill.

The term finishing has here been employed in the broadest sense; thatis, it is intended to include deburring, polishing, coating, or the likeand the media may vary substantially. It may comprise ceramic or metalpieces, wood, plastic particles, sand or other grit. Furthermore,

the operation may be performed dry or with water or water plusdetergents or' various other materials.

While a particular embodiment of this invention has been shown anddescribed, it is not intended to limit the same to the details of theconstruction set forth, but instead, the invention embraces suchchanges, modifications and equivalents of the various parts and theirrelationships as come within the purview of the appended claims.

I claim:

1. A vibratory finishing mill, comprising:

(a) an annular container having, at least in part, a

helical bottom terminating in a ledge;

(b) means for vibrating said container to cause media and work piecescontained therein to progress upwardly along said helical bottom andcascade over said ledge;

(c) means forming a discharge chute in a wall of said container spacedfrom said ledge;

(d) a grid partially bridging the space between said chute and ledge andoverlying the bottom of said container, said grid dimensioned totransfer work pieces to said chute and pass media to the bottom of saidcontainer;

(e) and a ramp disposed under said helical bottom and movable outwardlyfrom said ledge to bridge the gap between said ledge and said gridthereby to convey media and work pieces to said grid.

2. A vibratory finishing mill according to claim 1,

wherein:

(a) said ramp forms a segment of a helix;

(b) helical track means are provided to guide said ramp;

(c) and a drive means for thrusting and retracting said ramp is disposedunder the helical bottom of said container.

3. A vibratory finishing mill, comprising:

(a) an annular container having, at least in part, a

helical bottom terminating in a ledge;

(b) means for vibrating said container to cause media and work piecescontained therein to progress upwardly along said helical bottom andcascade over said ledge;

(c) a helical ramp disposed under said bottom and extensible from saidledge to convey media and work pieces beyond `said ledge;

(d) and means for discharging at least the work pieces from saidcontainer positioned to receive media and work pieces from said rampvwhen said ramp is extended.

4. A vibratory nishing mill according to claim 3,

wherein:

(a) means is provided to introduce liquid into the mass of media andwork pieces;

(b) and a drain is provided in the bottom of said container beyond saidledge.

5. A vibratory finishing mill according to claim 3,

wherein:

(a) a lip is provided at said ledge and overhangs the upper portion ofsaid ledge.

6. A vibratory mill, comprising:

(a) a container having, at least in part, a helical bottom terminatingin a ledge;

(b) means for vibrating said container to cause media and work piecescontained therein to progress upwardly along said helical bottom andcascade over said ledge, said means including a motor having eccentricweights mounted thereon;

(c) a ramp, said ramp being movable to extend from said ledge to conveymedia and work pieces beyond said ledge;

(d) and means for discharging at least the Work pieces from saidcontainer positioned to receive media and work pieces from said rampwhen said ramp is extended.

5 6 7. A vibratory mill according to claim 6, wherein: (b) and saidledge including an overhanging 11p above (a) said yramp forms a segmentof a helix, and track said opening.

means are provided on said container to guide said References Citedramp; UNITED STATES PATENTS (b) and a drive means for moving said rampis coupled 5 3,100,088 8/1963 Podmore et al 51 163 X thefefo- 3,161,99312/1964 Bau 51-163 8. A finishing mill according to claim 6, wherein:(a) said ramp is helical `and is disposed under said bot- OTHELL M-SIMPSON, Primary Examine"- tom of said container, said ledge includingan opening therein through which said ramp may be exm US' C1' X'R'tended; 241-175; 259-29, 72

